Railway traffic controlling system



March 17, 1936. G. c. WHITNEY RAILWAY TRAFFIC CONTROLLING SYSTEM Filed Aug. 5, 1931 Ilii- Patented Mar. 17, 1936 UNITED STATES ATENT FFICE Application August 3,

30 Claims.

This invention relates to railway traic controlling systems in general, more particularly to the operation of power operated track switches, and specifically to a novel means providing release operation of such track switches whether operated or controlled electrically or electropneumatically and to provide a signal in the approach to such track switches and has for an object to increase the safety of traffic over such track switches.

The invention herein disclosed refers to the same subject matter as my co-pending applications Serial Nos. 549,148 and 558,663, and relates to my prior Patent No. 1,421,880 issued July 4, 1922.

The established practice of the art requires that a means be provided to prevent the operation of a track switch when this operation would be dangerous to a train moving over the track.

This is particularly important where the track 25 for the passage of the train. This safety is usually obtained by a system of mechanical locking between the lever which controls the signal and the lever which controls the switch. Coupled with this there is an electric lock on the signal lever controlled by the presence of a train on the track and so arranged that this lever if the signal was cleared for the train, cannot be placed in a position to release the lever controlling the switch while the train occupies the portion of the track in the approach to the signal. Also, there is an electric lock on the switch lever controlled by the presence of a train on that portion of track in which the track switch is located. This arrangement is known as approach locking and detector locking according to its application.

In the arrangement above referred to it will be noted that the object sought is to prevent the operation of a track switch and the means used to obtain this eiect is applied in an indirect manner first to the lever controlling the signal and then to the lever controlling the switch.

My invention, U. S. Patent No. 1,421,880, provided a system of protection embodied in the circuits which operate the switch mechanism which prevents an operation of the switch with a train on the same portion of track or in the approach to said portion of track, without regard to the position of the signal lever and, in addition, if the switch has partially moved when the train approaches, it will complete its movement 1931, Serial No. 554,893

and thereby prevent -derailment, but when such movement is once completed the switch cannot be moved again until the track is clear. Also, said invention provided a release means arranged to require the positive co-operation of the engineman, or motorman, as will be appreciated.

My invention set forth hereinafter discloses a novel means of release and includes a special signal indication at the location of the release.

Notwithstanding the fact that I have illustrated and will describe this present invention in connection with the same certain form of allelectric operated switch operating mechanism system set forth in my prior Patent No. 1,421,880, it will be clear from the drawing and specification that I have invented a release device and signal means system of broad application equally applicable to the electro-pneumatic type of power operated track switch and, therefore, it is to be understood that the accompanying drawing, sho-wing in a wholly diagrammatic manner, one form my invention can assume, is not to be accepted in any way, whatsoever, in a limiting sense.

In order that my present invention will be understood more readily I have herein repeated the essential parts of the specification of my former patent and have shown in the accompanying drawing the same general outline on which I have displayed the same character references as in my former patent as far as possible and setting forth distinctly the scope of this present invention. In the drawing Fig. 1 is a wiring diagram showing the application of my invention to a switch operated by electric power and, in Fig. 2 I have shown a modified detail of the release means and signal indication means. Like characters represent similar parts in each figure.

The track rails are represented by IUI and |02; these are divided into sections or blocks designated A, B, and C by the insulated joints |03. II is a track switch leading to track E. A track circuit is provided for section A having track relay 22 energized from track battery 2I. And a corresponding track circuit is provided lfor section B, having the track relay 23 and track battery 20. A signal I6 is located at the entrance to the block B to protect switch I I located in this block.

The switch II is controlled by lever I la located in tower I2, this lever Ila having a normal and reversed position corresponding to the normal and reversed position of the switch. If this lever is moved towards the right contacts 28 will be closed by contact piece 30 and this sets up the conditions for operating the switch mechanism as follows: Current from battery I5, ammeter indicator 88, wires 5I and 52, contact 53 of safety relay 24, wire 54 to holding coil of relay 24, wires 55 and 56, contacts 2'8, contact piece 30, wire 5'I, contact 34 on switch mechanism, wire 60, motor field 32 for reverse movement, motor I4, wires 6I and 5U to battery. The motor, through connection 3 I, operates the track switch and on completion of the movement opens contact 34 and closes contact 35. This places the circuits in position to operate the track switch back to the normal position again when the lever is moved to the left, as shown. The operating circuit can be traced as before from wire 55, lever contacts 21 closed by Contact piece 30, wire 58, contact 35 on switch mechanism, now closed, wire 59, motor field 33 for normal movement, motor I4 and wires 6I and 5@ to battery. This circuit is fundamental to electrically controlled track switches whether operated by direct 0r alternating current and whether operated by one or more sources of power.

As po-inted out in my former patent the novelty in the use of the safety relay 24 resides in its maintaining the operating circuit if the motor I4 is drawing current from battery I5 and preventing the operating circuit being established if the motor I4 is not drawing current from battery I5 and either contact 'I2 of relay 22 or contact 'I4 of relay 23 is open due to the fact that the pick up coil of this relay 24 is controlled by the track circuits from wires 5I and 1I, contact I2 of relay 22, wire I3, contact 'I4 of relay 23, and wires I5 and I6, to relay 24, thence via wires I'I and 5G to battery I5. In addition to the track circuit control of the pickup coil of relay 24, above described, I provide a lever controlled pickup circuit, for the pickup coil of relay 24, which is effective, whenever lever IIa is in the normal or reverse position, to maintain relay 24 picked up independently of said track circuit control and thereby avoid needless operation of relay 24. This lever controlled pickup circuit may be traced as followsz-from battery I5, wires 5I and 80, contacts 25 closed by Contact piece 29, wire l5 to pickup coil of relay 24 and wires 'Il and 55 to battery I5, when lever I Ia is in the normal position. Contacts 25 closed by contact piece 29 and wires I8 and 'I9 provide a similar control when lever IIa is in the reverse position. Lever IIa has a preliminary movement defined by the electric lock SI engaging the slot 92. This lock is released when the switch mechanism has completed its movement by a circuit arrangement, not shown, which enables the lever movement to be completed. It will be observed that contacts 25 and 26 are shorter than contacts 2i and 28 which control the switch motor and contacts 25 and 26 are closed only in the extreme position of the lever; therefore, while the lever moves within the limits of slot 92 contacts 25 and 26 cannot be closed and thus when the lever is in the operating position this circuit of the pickup coil of relay 24 is open between wires i8 and '19. Thus, when the lever is moved to operate the switch the pickup coil of relay 24 is controlled over the track relays 22 and 23, this circuit of the pickup coil will, therefore, be open with a train occupying track section A or B.

It has been shown that the operating current for the switch mechanism is taken in series through the holding coil of safety relay 24 and through contact 53 when this relay is energized. The following conditions, therefore, result: When the lever I Ia is placed in either extreme position, relay 24 is energized by the pickup coil; when the track sections A and B are unoccupied this relay 24 is also energized by the pickup coil; when the switch mechanism is drawing current this relay 24 is maintained energized by the holding coil; when this relay 24 is deenergized the switch cannot be operated by power. Attention is here directed to the fact that contact 53 doesV not open while the switch is drawing current; no provision, therefore, is necessary to guard against arcing of the contact even when this circuit is operated on high voltage. Attention is also directed to the fact that I may separate the functions of the electrical element (relay 24) into two or more relays with the same ultimate result as I have obtained with but one relay. By virtue of contact 53, relay 24 becomes a stick relay.

The application of this system will be understood by considering the approach o-f a train in the direction of the arrow. When the signal I6 is clear, the route is established for the through movement of the train and when the train is on section A or B a movement of the lever I Ia cannot produce a corresponding movement of the switch since the pickup coil of relay 24 is opened by the track relays and is also opened by the preliminary movement of the lever before the -operating circuit is established; hence contact 53 will be open thus preventing current flow to the switch operating motor. Now, if the switch movement is partially made When the train enters section A, although the pickup coil of relay 24 will be deenergized, the holding coil of this relay Vis energized until the operating circuit of the switch motor I4 is opened at contacts 34 or 35 upon completion of the track switch movement. Section A is of such length that a train at maximum speed passing over it will consume a greater time interval than that necessary for the complete operation of the track switch movement.- Where necessary, an additional section of track may be arranged to control the circuit of relay 24 for this purpose. By this arrangement switchA II will be in position and locked before the train enters upon section B and it cannot againbe moved until the train passes off this section. 'Ihis system, therefore, becomes a substitute for approach locking, provides track circuit control of the switch mechanism, and insures a completed movement of the switch independently of the track circuit control, all in the most direct manner and independent of the position or subsequent movement of the signal or its controlling lever and also independent of the position of the switch mechanism or the position or subsequent movement of its controlling lever.

In practice it frequently happens that .the route cannot be established for an approaching train and the signal remains in the stop position. In dense traffic, for instance, a previous train may not have cleared the route when the following train enters upon section A; signal I 6 is used to stop said following train. It occasionally happens that a train will over-run the signal or a train may pass signal I 6 in the stop -position on the instruction of a hand signal or flag. Without the protection afforded by this invention under these conditions the switch lever IIa/'is free to be moved and to operate the switch mechanism until the train enters section B when an electric detector lock, not shown in the drawing but commonly used in practice, restricts lthe movement of the lever. Now, if the lever IIa is placed in an operating position just before the train enters upon secti-on B, if the time consumed by the train in covering the distance D is less than the time interval for the operation of the switch mechanism, it is apparent that the front of the train will pass over the switch rails before their movement is fully completed thereby leading to a derailment. With the invention of my former patent above mentioned. this cannot occur as the track circuit control of the switch extends over section A as well as section B.

It will be clearly evident, also, that if the train passes over the track circuits beginning with section C and ending with track circuit A, in other words, if the train runs over the system in the direction opposite to that previously described and while it is occupying section A or B the lever or actuating device should be operated, the switch would not operate because the switch operating circirt would be open at contact 53 on relay 24, but as soon as track circuit A became unoccupied-track circuit B remaining unoccupied-relay 24 will become energized closing the switch operating circuit at contact 53 thus operating the switch to a position to correspond with the lever or actuating device, thereby effecting, in a safe manner, an entirely automatic operation of the track switch. By employing any of the well-known systems of directional released route locking the above described switch operati-on may be made effective when the train has cleared track circuit B.

In the above description I have explained the functioning of the system in the ordinary course of events as set forth in my former patent and the description of this present invention will now proceed.

In the ordinary course of operation, it is, of course, necessary to be able to operate the switch when a train is stopped at signal I and occupying section A. I provide for this by requiring the positive co-operation of the engineman or motorman together with the operation of the lever to set up the conditions for operating the switch mechanism.

As shown in Fig. l, I have provided a circuit including wire 82 extending from wire 54 at relay 24, to an indication means (in this case series relay 83 located in the vicinity of signal I8) thence via wires 84, i I, and 5I to battery I5. Relay 83 has three contacts 85, 88, and B'I-contacts 85 and 86 being open and contact 81 being closed when relay 83 is deenergized and, contacts 85 and 86 being closed and contact 8'.' being open when relay 83 is energized.

When the train is standing at signal I5, contact 72 of track relay 22 being open, and it is desired to operate switch I I to the reverse position to route the train to track E, the towerman moves lever IIa to the right (reverse operating position) so that contact piece opens contact 21 and closes contact 28. (Contact piece 29 opens contact 25 but does not close Contact 26 in this operation for the reason hereinbefore explained). This movement of lever Ila opens the lever control circuit of the pick up coil of relay 24, and the track relay circuit control of this pick up coil being open, contact 53 on relay 24 opens when contact 25 opens. This movement of the lever l Ia, sets up a circuit from battery I5 to indicator 88, wires 5I, 1I, 84, to relay 83, wire 82 to holding coil of relay 24 (contact 53 being open) thence via wires 55 and 55, contacts 28, now closed by contact piece 38, thence via wire 51, contact 34, wire 60, motor field 32 for reverse movement,

motor I4, and wires 5I and 50 to battery I5. Relay 83 is of the slow release type and the resistance of its coils is selected such that current flow in the above mentioned circuit is suicient to energize relay 83 to close contacts 85 and 86 but is not sufficient to energize relay 24 to close contact 53 or to start the switch operating mechanism in operation. Current flow in this circuit is indicated by tower indicator 88 and this current flow energizes relay 83 to close contacts 85 and 86. With the closing of contact 86 an indicator circuit including lamp signal vwires 58, 9|, 92, and local source of energy 93 is established. The situation now stands with current flow in the switch operating circuit indicated to the towerman (indicator 88) and indicated to the motorman of the train standing at signal I6 by illumination of lamp indicator 89. By rule or design of indication lamp 89 the motorman is instructed to operate key releasing means, a self restoring push button, 94, which establishes a low resistance shunt circuit including wires 95, S5, 91 and contacts 98 and 85 (now closed) around relay 83. When this shunt circuit is established increased current, suicient to operate stick relay 24 and close contact 53, flows in the circuit of relay 24 and this is shown on tower indicator 88. With the closing of contact 53 the functioning of the system is the same as previously explained, tower indicator 88 indicating further increase of current flow due to functioning of the switch mechanism until contact 34 opens. The slow release of relay 83 is to insure that contact 85 is held closed a short time, after the shunt circuit is established, so that contact 53 on relay 24 may close. With the closing of contact 53 the circuit including relay 83 becomes deenergized due to the fact that a circuit including wire 52, contact 53 of relay 24, and wire 54 is now set up between wires 5I and 82 thus shunting out relay 83 and lamp signal 89 is extinguished thus standing as an indication to the mctorman that the switch mechanism has operated. When the switch has moved to the reverse position, contact 34 opens thus deenergizing relay 24 and contact 53 opens and, thereafter switch motor I4 cannot be energized as long as either track section A or B is occupied, unless the lever IIa, is put in proper position and the same positive co-operaticn of the motorman obtained as before.

When relay 83 becomes deenergizeol by virtue of its shunt circuit being established or by closing of contact 53 lamp 88 will be extinguished but will be re-lighted after the push button 94 operation has restored to its normal position if contact 53 on relay 24 has not closed. After the completion of an operation thus performed the towerman may complete the movement of lever Ila and clear signal I8 or the motorman may proceed by instruction or hand signal but the train being stopped cannot accelerate to over-run the switch points before the switch movement is completed.

Attention is directed to the fact that my invention as thus arranged provides an indication means incorporated in the switch controlling circuit, which means is also automatically controlled by the lever controlling said circuit at times while, at other times said means is not controlled by the operation of said lever.

Track section A may be eliminated in case the distance D is sufficient, as will be understood, and in that instance wire 'I3 would be connected to battery wire 5I, as will be appreciated.

In Fig. 2, I have shown a modification in that relay 83 of the system of Fig. l has been eliminated and lamp 89 is connected in place thereofin this instance the resistance of lamp 89 would be selected to suit the conditions hereinbefore eX- plained. Similar character references are used as in Fig. 1.

The circuit including wires 99, |00, Il and contacts 81 on relay 83 and |92 on push button 94 are provided and included in the control of signal I8 as a check on the restoring or" the releasing means to a non-releasing position, as will be understood. In View of this check circuit it will be evident that lamp 89 and signal I6 cannot be cleared at the same time.

In the event that occasion requires that the motormans indication and release be operative from more than one location, the required plurality of the means, above explained, each including a relay 83 and push button 94 would be connected in multiple on Wire 82-the resistance of relays 83 being suitablyselected.

Contacts 25 and 2t on lever I la may be omitted entirely and the systeml will function properly by the pick up coil of relay 24 controlling through the track circuit relays only. The advantage secured by controlling this relay with the lever in the eXtreme position is that if the switch should be misplaced and the track relay open, conditions will be automatically established to move the switch into a position corresponding with the position of the lever.

The track circuit control of the switch mechanism is always effective to control the operating current except for the interval during which the mechanism is drawing current. This is a form of protection superior to that indirectly obtained from track circuit controlled locks applied to operating levers.

It will be observed that push button 94 and lever lla may be operated in any sequence and independent of each other. If the lever be operated iirst, the operation of the remotely located indication means is an indication of said lever operation.

As will be noted, the releasing means including push button 94 is connected in series with the respective switch mechanism operating circuits when contact 53 is open, and it will be noted further that appropriate contacts of lever lla are also connected in series in said operating circuit. Therefore, the functioning of said remotely located indication means is evidence that the operating circuit of said mechanism is complete. Tower ammeter indicator S8 is connected in series in this same circuit, therefore; the showing on indicator 88 is evidence that the operating circuit is complete notwithstanding that push-button control 94 has not been operated.

The above rather specific description of one form of my invention, is given solely by way of illustration, and is not intended, in any manner whatsoever, in a limiting sense. Obviously, my invention can assume many different physical forms, and is susceptible of numerous modifications, and all such forms and modifications are intended to be included, in this application, as come within the scope of the appended claims.

Having described my invention I now claim:

1. In a railway traiic controlling system, a track provided with a track circuit, a track switch, an electrically controlled mechanism for operating said switch, means including a relay for controlling said mechanism by said track circuit, means for removing said control when said mechanism is operating, and means for shunting out said track circuit control, the last mentioned means including a relay controlled signal to indicate that said shunting means is to be operated.

2. In a railway traffic controlling system, a track including a track circuit, a switch, an electrically operated mechanism for said switch, a device incorporated in the circuit of said mechanism and controlled by said track circuit for maintaining the energy to said switch mechanism when said track circuit is occupied, and means for shunting out said track circuit control, said means including indication means incorporated in the operating circuit of said mechanism.

3. In a railway traffic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for said switch, a device embodied in the circuit of said mechanism and controlled by said track circuit for preventing the operation of said mechanism when said track circuit is occupied and for maintaining the circuit of said mechanism throughout its operation, and means for shunting out said track circuit control, said means including indication means embodied in the circuit of said mechanism.

4. In a railway traflic controlling system, in combination, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a circuit controlling said mechanism, a relay having an operating coil controlled by said track circuit and a holding coil connected in series with the circuit controlling said mechanism, and means for shunting out said track circuit control, said means including a plurality of indication means embodied in the operating circuit of said mechanism.

5. In a railway traic controlling system, in combination, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a circuit controlling said mechanism, a lever controlling said circuit, a relay having an operating coil controlled by said track circuit and by said lever and a holding coil connected in series with the circuit controlling said mechanism, and means for shunting out said track circuit control, said means including a plurality of control points in the control circuit of said mechanism, each of said points having indication means.

6. In a railway traiiic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism: for operating said switch, a relay having an operating coil controlled by said track circuit and a holding coil included in the circuit of said mechanism, said relay when energized closing said mechanism circuit, said holding coil at times being energized by means remotely located in combination with a lever contact, said combination shunting out said track circuit control.

7. In a railway traffic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a lever controlling the circuit of said mechanism, a relay controlled by said lever and by said track circuit, said relay controlling the circuit of said mechanism, and means for shunting said track circuit control, said shunting means including indication means, said shunting means controlling said indication means.

8. In a railway trailic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a lever controlling the circuit of said mechanism, a relay controlled by the circuit of said mechanism when energized, said relay also controlled by remotely located means in series with said lever, said means including an indication means.

9. In a railway traic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a lever controlling the circuit of said mechanism, a stick relay controlled by the circuit of said mechanism when energized, said relay also controlled by remotely located means, said remotely located means indicating that said stick relay has functioned.

10. In a railway trafiic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a lever controlling the circuit of said mechanism, remotely located release means, and a plurality of relays including a stick relay included in the circuit of said mechanism, one of said relays controlled by said track circuit and another of said relays controlled by said release means.

11. In a railway traffic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a lever controlling the circuit of said mechanism, a stick relay controlled by the circuit of said mechanism and by said track circuit, and means included in the operating circuit of said mechanism indicating that said relay has functioned.

12. In a railway traffic controlling system, av

track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a lever controlling the circuit of said mechanism, a plurality of relays including a stick relay included in the circuit of said mechanism, and means included in the operating circuit of said mechanism indicating that each relay of said plurality of relays has functioned.

13. In a railway traic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a lever controlling the circuit of said mechanism, and a stick relay controlled by the circuit of said mechanism when energized, said relay also controlled by means remotely located in series `with said lever, said means included in the circuit of said mechanism.

14. In a railway tramo controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a lever controlling the circuit of said mechanism, a relay controlled by said track circuit, a holding circuit for said relay to maintain it energized when said mechanism is drawing current, said relay controlling the circuit of said mechanism, said relay also controlled by means remotely located in combination with said lever, said means having indication means included in the circuit of said mechanism, said indication means arranged to indicate operation of said lever and said remote control means independently and in combination.

15. In a railway traic controlling system, a track including a track circuit, a switch, an electrically controlled mechanism for operating said switch, a relay having a pick up coil controlled by said track circuit and a holding coil controlled by the circuit of said mechanism, said relay controlling said mechanism circuit, means for preventing said relay from opening said circuit When said mechanism is drawing current, and means remotely located at times controlling said holding coil.

16. In a power operated interlocking system including a central source of energy, a switch machine, a detector track circuit., means controlled by said track circuit and responsive to the flow of current to the switch machine for cutting of the supply of power to said machine while the detector track circuit is occupied, said means permitting the switch machine to complete its operation if started before the detector track circuit is occupied, means remotely located in combination with said rst mentioned means for shunting out said track circuit control, and remotely located signal means to indicate that the remotely located shunting out means .is to be operated.

17. In a railway traiiic controlling system, `a switch, a plurality of track circuits one of which track circuits is located in the approach to the signal protecting the switch, an electrically operated mechanism for said switch, a circuit for said mechanism, said circuit controlled by said track circuits for preventing the flow of current to said mechanism when said track circuits are occupied, and means remotely located included in said mechanism circuit for shunting out said track circuit control.

18. In a power operated track switch controlling system, a track including a track circuit, a track switch, a mechanism for operating said track switch, a circuit controlling said mechanism, said circuit controlled by said track circuit, said circuit including a relay, said relay controlling a signal, and a manually operated contact controlling said signal and said mechanism circuit, said manually operated co-ntact nullifying said track circuit control once for each operation of said manually operated contact.

19. In a power operated track switch controlling system, a track including a `track circuit, a track switch, a mechanism for operating said track switch, a circuit controlling said mechanism, said circuit controlled by said track circuit, said circuit also controlled by two manually operated contacts in series and controlling said mechanism independently of said track circuit control, one of said contacts being regularly used in the selective control of said circuit which controls said mechanism.

20. In a power operated track switch controlling system, a track including a track circuit, a track switch, a mechanism for operating Asaid track switch, a circuit controlling said mechanism, said circuit controlled by said track circuit, said circuit also controlled by two manually operated contacts and a relay in series and controlling said mechanism independently .of Said track circuit control.

21. In a power operated track switch controlling system, a track including a track circuit, a track switch, a mechanism for operating said track switch, a circuit controlling said mechanism, said circuit controlled by said track circuit, said circuit also controlled by two manually operated contacts and a relay in series and controlling said mechanism independently of said track circuit control, and a mechanism operated contact included in said circuit and restoring said track circuit control when said mechanism has completed its movement.

22. In a power operated track switch controlling system, a track including a track circuit, a track switch, a mechanism for operating said switch, a circuit controlling said mechanism, said circuit controlled by said track circuit, said circuit also controlled by two manually operated contacts and a relayY in combination and controlling said mechanism independently of said track circuit control, and a contact on said relay included in said circuit and removing said independent control after every operation of said independent control.

23. In a power operated track switch controlling system, a track including a track circuit, a track switch, a mechanism for operating said track switch, a circuit controlling said'mechanism, said circuit controlled by said track circuit, Said circuit including a relay, said relay controlling a signal, and a manually operated Contact controlling said signal and said mechanism circuit, said manually operated contact nullifying said track circuit control.

24. In a power operated track switch controlling system, a track including a track circuit, a track switch, a mechanism for operating said track switch, a relay having an operating coil controlled by said track circuit and a holding coil included in a circuit controlling said mechanism, said relay when energized closing said mechanism circuit, said holding coil at times being energized by a circuit including a lever contact and a release Contact.

25. In a railway traic controlling system including track circuit control of a power operated track switch operating mechanism, a circuit controlling said mechanism, said circuit controlled by a lever and by said track circuit, a circuit established by said lever in its extreme positions to control said mechanism independently of said track circuit, a circuit including a relay controlled by said lever in an operating position when said track circuit is occupied, a signal, said relay controlling said signal, a circuit including a contact on a manually operable releasing devicer and a contact on said relay in series for nullifying said track circuit control of said mechanism circuit, and a checking circuit including a normally closed Contact on said device and a normally closed contact on said relay.

26. In a railway tra'ic controlling system including track circuit control of a power operated track switch operating mechanism, a circuit controlling said mechanism, said circuit controlled by a lever and by said track circuit, a circuit including a relay controlled by said lever in an operating position when said track circuit is occupied, a signal, said relay controlling said signal, a circuit including a contact on a manually operable releasing device and a contact on said relay in series for nullifying said track circuit control of said mechanism circuit, said manually operable contact controlling said relay, and a checking circuit including a normally closed contact on said device and a normally closed contact on said relay.

2'7. In combination, in a power operated track switch operating system normally selectively controlled from one location, a detector track circuit. said track circuit controlling said track switch system, a releasing circuit including a remotely located manually operable contact to nullify said track circuit control, and a signal located adjacent said manually operable contact and controlled from said one location to indicate that said remotely located manually operable contact is to be operated.

28. In a power operated track switch controlling system normally selectively controlled from one location, a detector track circuit, said track circuit controlling the control circuit of said switch controlling system, a releasing circuit including a remotely located manually operable contact to nullify said track circuit control, and a signal located adjacent said manually operable contact and controlled from said one location to indicate that said remotely located manually operable contact is to be operated.

29. In combination, a stretch of railway track including a switch, a control lever, an instrument controlled by traic movements over said track,

a circuit including a contact operated by said instrument and controlled by said lever for controlling said switch, an indication device, a branch path for said circuit including said indication device in multiple with said contact and having sufficient resistance to prevent control of said switch but permitting operation of said indication device if said instrument contact is open, a manually controlled key, and means controlled .by said key and by said indication device for controlling said switch.

30. In combination, a stretch of railway track including a switch, a control lever, an instrument controlled by trac movements over said track, a circuit including a contact operated by said instrument and controlled by said lever for controlling said switch, an indication device, a branch path for said circuit including said indication device in multiple with said contact and having suiicient resistance to prevent control of said switch but permitting operation of said indication device if said instrument contact is open, a manually controlled key, and means controlled by said key and by said indication device for controlling said switch while said indication device is energized.

GILBERT C. WHITNEY. 

